The invention relates to a driving roller stand for continuous casting plants with at least two adjacently arranged strand guides, in particular continuous casting plants for steel billets, comprising at least one separately driven driving roller for each of the strands, a first driving roller being designed as a hollow construction unit with a first driving element and a driving shaft provided with a second driving element of a second driving roller that is arranged coaxially with the first driving roller penetrating this hollow construction unit, each driving roller furthermore being separately journaled on the driving roller stand.
With multiple continuous casting plants it is desirable to arrange the strand guides for the individual strands as closely adjacent to each other as possible in order to keep the size of the common tundish arranged above all the moulds as small as possible, thus minimizing heat losses as well as the amount of space required for the continuous casting plant.
A driving roller stand of the initially-defined kind is known from German Offenlegungsschrift No. 1,483,664. With this stand an Oldham coupling is arranged between the first driving roller, which is designed as a hollow construction unit, and the neighbouring second driving roller, which Oldham coupling connects the neighbouring driving roller with the driving shaft that penetrates the hollow construction unit. However, with this coupling it is not possible to arrange the individual strands closely adjacent one another. This known driving roller stand, therefore, exhibits an undesirably large construction width transverse to the longitudinal direction of the strand.
A driving roller stand having a space-saving, closely neighbouring arrangement of the two strand guides is known from German Offenlegungsschrift No. 27 02 894. With this stand, the driving shaft of the second driving roller is rigidly connected with this driving roller and rotatably journaled in the hollow construction unit of the first driving roller. This results in the disadvantage that the removal of one of the driving rollers necessitates the removal of the other driving roller, so that the casting operation cannot be maintained at one of the two strand guides. Also, the removal of both of the driving rollers, although damage has occurred to only one of the two driving rollers, is cumbersome and time-consuming. This arrangement also requires the use of several differently dimensioned antifriction bearings for journaling the driving rollers, which necessitates maintaining a stock of these different spare parts.
With the multiple continuous casting plant known from German Auslegeschrift No. 27 21 856, one driving shaft each reaches from the driving motors arranged laterally of the plant to each of the driving rollers provided at the strand guides, from the outside, and connects the same with the respective driving roller by means of a chain drive or a coupling arranged immediately beside the respective strand guide. This has the disadvantage that the strand guides can no longer can be arranged very closely adjacent to each other because the driving elements are situated between the strand guides, and the couplings or driving elements situated between the strands are subjected to the immediate heat influence of the strands.
A further possible arrangement of the driving rollers in multiple continuous casting plants is shown in German Offenlegungsschrift No. 27 33 864, where each of the driving rollers is directly connected by means of a driving shaft. There, the driving rollers, however, are not arranged coaxially, but lie one behind the other in the strand extraction direction. This results in a greater construction length of the plant.